Definition: a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Answer:
Hey!
Your answer should be D!
Explanation:
In a transformer Np / Ns is called the voltage ratio. If Ns is less than Np then Vs is less than Vp. This is called a step-down transformer as the voltage is reduced.
(source from google.com!)
We can approach this in another way.
We know that sin(∅) = height / hypotenuse.
Thus, for x, height is 1 and hypotenuse is 3. Using Pythagoras theorem,
3² = 1² + b²
b = √8
cos(x) = b/hypotenuse
cos(x) = √8 / 3
Now, lets consider y:
sec(y) = 1 / cos(y) = 1 / base / hypotenuse = hypotenuse / base
The hypotenuse is 25 and the base is 24. We again apply Pythagoras theorem to find the third side, which works out to be:
height = 7
sin(y) = height / hypotenuse
sin(y) = 7/25
Now, sin(x + y) =
sin(x)cos(y) + sin(y)cos(x)
= (1/3)(24/25) + (√8 / 3)(7/25)
= 8/25 + 7√8/75
= (24 + 14√2) / 75
Answer:
RE of Hydrogen = 6.47 x RE of Krypton
Explanation:
Actually the correct formula for comparing rate of effusion (RE) of two gases is:
RE of Gas A
------------------- = √ ( Molar mass of B / Molar mass of A)
RE of Gas B
You can designate which of the two gases you have (hydrogen and krypton) will be your gas A and gas B. So for this particular problem, let us make hydrogen as gas A and Krypton as gas B. So the equation becomes:
RE of Hydrogen
------------------------- = √ (Molar mass of Krypton / Molar mass of Hydrogen)
RE of Krypton
Get the molar masses of Hydrogen and Krypton in the periodi table:
RE of Hydrogen
------------------------- = √ (83.798 g/mol / 2 g/mol)
RE of Krypton
RE of Hydrogen
------------------------- = 6.47 ====> this can also be written as:
RE of Krypton
RE of Hydrogen = 6.47 x RE of Krypton
It means that the rate of effusion of Hydrogen gas will be 6.47 faster than the rate of effusion of Krypton gas. With the type of question you have, it doesn't matter which gases goes on your numerator and denominator. What's important is that you show the rate of effusion of a gas with respect to the other. But if that's concerns you the most, then take the gas which was stated first as your gas A and the latter as your gas B unless the problem tells you which one will be on top and which is in the bottom.
